Subterranean termites cause millions of dollars in damages to wooden structures in the United States. This destruction is not limited to wooden structures alone--many commercial termiticides used to combat these pests are potential environmental contaminants and carcinogens. For example, the most common method of subterranean termite infestation prevention, which involves applying a chemical termiticide to a structure's peripheral grounds, often leads to soil and water contamination when applied improperly. Accordingly, it is desirable to find new means for controlling termites which do not pose such potential hazards.
Tung trees are grown in abundance in the Western Hemisphere along the Gulf Coast of the United States, particularly in the southeastern states of Louisiana, Mississippi, Alabama, Georgia and Florida, and in South America. Until the present invention, the prime commercial interest in tung trees has been in the oil which is extracted from the fruit of the plant. Tung oil is a pale yellow, pungent, drying oil composed chiefly of unsaturated fatty acid glycerides useful as a waterproofing agent and as a component of quick-drying varnishes and paints.
Two processes, mechanical and chemical, are predominantly in use in the Western Hemisphere for tung oil extraction. In the United States, the principal means of tung oil extraction involves the application of mechanical force, such as by the use of a press mill, to the tung kernels to physically squeeze the oil therefrom. This initial pressing forces about 85 percent of the oil present out of the kernels. The balance of the oil, usually about 15 percent of the original quantity, is extracted with a solvent, such as hexane. Other tung nut processing plants, principally found in South America, extract the oil by means of a 100 percent chemical process.
U.S. Pat. No. 4,293,567 describes an anti-feedant prepared from tung oil which is useful to deter boll weevils from puncturing the bolls of cotton plants.